﻿// Copyright © 2015, 2017 Oracle and/or its affiliates. All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Diagnostics;
using System.Reflection;

namespace MySql.Data.EntityFrameworkCore.Utils
{
  [DebuggerStepThrough]
  internal static class SharedTypeExtensions
  {
    public static Type UnwrapNullableType(this Type type) => Nullable.GetUnderlyingType(type) ?? type;

    public static bool IsNullableType(this Type type)
    {
      var typeInfo = type.GetTypeInfo();

      return !typeInfo.IsValueType
             || (typeInfo.IsGenericType
                 && typeInfo.GetGenericTypeDefinition() == typeof(Nullable<>));
    }

    public static bool IsInteger(this Type type)
    {
      type = type.UnwrapNullableType();

      return type == typeof(int)
             || type == typeof(long)
             || type == typeof(short)
             || type == typeof(byte)
             || type == typeof(uint)
             || type == typeof(ulong)
             || type == typeof(ushort)
             || type == typeof(sbyte)
             || type == typeof(char);
    }

    public static bool CanBeAutoIncrement(this Type type)
    {
      return IsInteger(type)
        || type == typeof(float)
        || type == typeof(double);
    }
  }
}
